Solve this equation graphically
Answers
1.1 Solve 3x+4y-20 = 0
Tiger recognizes that we have here an equation of a straight line. Such an equation is usually written y=mx+b ("y=mx+c" in the UK).
"y=mx+b" is the formula of a straight line drawn on Cartesian coordinate system in which "y" is the vertical axis and "x" the horizontal axis.
In this formula :
y tells us how far up the line goes
x tells us how far along
m is the Slope or Gradient i.e. how steep the line is
b is the Y-intercept i.e. where the line crosses the Y axis
The X and Y intercepts and the Slope are called the line properties. We shall now graph the line 3x+4y-20 = 0 and calculate its properties
Notice that when x = 0 the value of y is 5/1 so this line "cuts" the y axis at y= 5.00000
y-intercept = 20/4 = 5 Calculate the X-Intercept :When y = 0 the value of x is 20/3 Our line therefore "cuts" the x axis at x= 6.66667
x-intercept = 20/3 = 6.66667 Calculate the Slope :Slope is defined as the change in y divided by the change in x. We note that for x=0, the value of y is 5.000 and for x=2.000, the value of y is 3.500. So, for a change of 2.000 in x (The change in x is sometimes referred to as "RUN") we get a change of 3.500 - 5.000 = -1.500 in y. (The change in y is sometimes referred to as "RISE" and the Slope is m = RISE / RUN)
Slope = -1.500/2.000 = -0.750 Geometric figure: Straight Line Slope = -1.500/2.000 = -0.750 x-intercept = 20/3 = 6.66667 y-intercept = 20/4 = 5